3 factor Featured Image Fallback in WordPress

gistfile1.txt

/*
 * This code allows your posts to have a fallback featured image based on your category. 
 * It requires manual upload of the featured images. In this case it assumed /category-images to have
 * been created in the root WP install directory.
 * It is based on this tutorial at WPBeginner:
 * http://www.wpbeginner.com/wp-themes/set-fallback-featured-image-based-post-category-wordpress/
 * The original tutorial assumed all categories have a featured image.
 * This codes inserts a div (to be styled) when there is also no featured image for the category.
 * Nathan Briggs was instrumental in implementation of the file_exists method.
 */
 
<?php if ( has_post_thumbnail() ) : ?>
			
	<?php the_post_thumbnail(); ?>

	<?php else : 
		$category = get_the_category(); 
		$featured = ABSPATH . 'category-images/' . $category[0]->category_nicename . '.jpg';
		if (file_exists($featured)) {
			clearstatcache(); ?>
			<img src="<?php bloginfo('url'); ?>/category-images/<?php echo $category[0]->category_nicename ; ?>.jpg" alt="<?php the_title(); ?> category header" class="category-thumb" />
			<?php
			} else {
				clearstatcache();
				echo '<div class="featured">
				<h1>CYS Resources for <span>' . $category[0]->category_nicename . '</span></h1>
				</div>';
				}
			?>
<?php endif; ?>